Petroleum stock shortages and resulting increased prices enhance the attractiveness of methods and devices for reprocessing previously disgarded plastic materials for use in manufacturing operations such as film waste, waste from extruding or waste and refuse from sealing and printing operations.
Various methods and apparatus as disclosed in U.S. Pat. Nos. 3,510,067 and 3,685,748 have been provided for reprocessing plastic materials, for example polyethelyene, by comminution of the material and subsequent cooling of the material by fluid addition.
However, such prior apparatus does not provide means to sequentially control the steps of the processing operation to improve the efficiency of the operation by reducing processing time for multiple batches.
More specifically, such previous apparatus have not recognized certain advantages of controlling the extent of comminution of plastic material prior to addition of the fluid or the treatment of the plastic material subsequent to comminution and particularly the processes and sequences necessary after introduction of the fluid.
Likewise, such previous apparatus has not recognized the benefits of agitation of the plastic material during the comminution to maintain a constant power input to the rotating blade during the comminution cycle.